Adjustable roll feed

ABSTRACT

An adjustable roll feed for stamping presses and the like for imparting intermittent linear feed to strip stock, said feed having first adjustment means for permitting the length of feed per revolution of the rolls to be adjusted between zero and a maximum length based on the diameter of the rolls and having a second adjustment means permitting a fine adjustment of the length of feed to be effected while the feed is in operation.

Umted States Patent [151 3,653,569

Homstead et al. [4 1 Apr. 4, 1972 541 ADJUSTABLE ROLL FEED 3,058,641 /1962 Peterson ..226/l 3,094,925 6/1963 Huber ..226/l53 X [72] Inventors: Robert H. Homstead, Greenv1lle; Carl G.

g s Esmond; Anthony Gomez, Primary Examiner-Richard A. Schacher w1ck, all of R.l. Assistant Examiner-Gene A. Church 73 Assignee: Carl G. Peterson Co., Smithfield, R.l. Mlchaelm [22] Filed: Feb. 9, 1970 [57] ABSTRACT {211 A N 9,676 An adjustable roll feed for stamping presses and the like for imparting intermittent linear feed to strip stock, said feed having first adjustment means for permitting the length of feed U.S. per revolution of the rolls to be adjusted between zero and a [5 l Int. Cl ..Bh 17/26 axim l th based on the diameter of the rolls and having Field 01 Search 179 a second adjustment means permitting a fine adjustment of the length of feed to be effected while the feed is in operation. [56] References Cited UNITED STATES PATENTS Lang 226/153 6 Claims, 7 Drawing Figures Patented April 4, 1972 3,653,569

2 Sheets-Sheet l F I G. 8

INVENTORS ROBERT H. HOMSTEAD CARL G. PETERSON F l G. 4 ANTHONY GOMEZ ATTORNEYS 3,653,569 Patented Aprll 4, 1972 2 Sheets-Sheet 2 INVENTORS ROBERT H. HOMSTEAD CARL. G. PETERSON ANTHONY GOMEZ a /J 1 r ATTORNEYS ADJUSTABLE ROLL FEED BACKGROUND OF THE INVENTION This invention relates to feed mechanisms for stamping presses and the like, as well as other apparatus using a roll feed. In such apparatus, the roll feed imparts a predetermined linear movement to strip stock in timed sequence to the operation of the stamping press or the like. The type of operation being performed on the strip stock determines the required length of feed and the required length of time that the stock must remain stationery. It is therefore important that the roll feed be readily adjustable to achieve the desired length of feed of the stock and the desired length of time that the stock remains stationary.

One type of roll feed that has often been used in connection with stamping presses and the like is illustrated by U.S. Pat No. 2,591,993, dated Apr. 8, 1952. In roll feeds of this type, a pair of vertically aligned rollers are geared to each other for imparting linear feed to a strip that passes therebetween. Intermittent feed is imparted to the strip of an indexing mechanism mounted at the end of the shaft of one of the rollers, said indexing mechanism being driven by a pawl and ratchet arrangement which in turn is driven by an arm eccentrically mounted on the fly wheel of the stamping press. By adjusting the length of oscillatory stroke of said arm, the length of feed may be adjusted.

Although roll feeds of this general type have proven to be effective for many years, recent developments in stamping presses and the like have resulted in presses which operate at a speed of more than 1,000 revolutions per minute thus placing great strain on the indexing mechanism and particularly the pawl and ratchet means that forms a part thereof.

SUMMARY OF THE INVENTION The present invention completely eliminates the use of indexing mechanism of the general type shown in U.S. Pat. No. 2,591,993 and instead comprises a feed wherein the rolls are continuously being driven but wherein the rolls make feeding engagement with the strip only during a part of the revolution of said rolls. This approach eliminates the constant stopping and starting of the rolls that exists where indexing mechanism of the type shown in U.S. Pat. No. 2,591,993 is employed, and by eliminating this stopping and starting of the rolls, greater feed speed can be achieved, and longer life of the roll feed component parts is realized.

An important feature of this invention is the provision of simple, yet effective means for adjusting the roll feed so that feed of any desired length of the strip may be achieved per revolution of the roll shafts, it being obvious that the maximum feed per revolution will be a function of the diameter of the rolls, as will hereinafter be described in more detail.

In addition to the adjustment means generally described above, the present apparatus incorporates a fine adjustment that is operable while the roll feed is actually in motion. Thus, if while the stamping press or the like is actually operating it is found that a slightly greater or lesser length of feed of the stock is required, this adjustment may be made without involving the time and expense inherent in a complete shutdown of the equipment.

Other objects, features and advantages of the invention shall become apparent as the description thereof proceeds when considered in connection with the accompanying illustrative drawings.

DESCRIPTION OF THE DRAWINGS In the drawings which illustrate the best mode presently contemplated for carrying out the present invention:

FIG. 1 is a front elevational view of a roll feed embodying the present invention;

FIG. 2 is an elevational view thereof looking from the right with respect to FIG. 1;

FIG. 3 is a section taken on line 33 of FIG. 1;

FIG. 4 is a perspective detail view showing the roll and shaft assemblies;

FIG. 5 is a fragmentary elevational view in section, showing the adjustable mounting for the upper roll;

FIG. 6 is a fragmentary elevational view, in section, showing the adjustment means for the lower roll;

FIG. 7 is an exploded perspective view showing some of the component parts of the adjustment means for the lower roll; and

FIG. 8 is an end view of the rolls per se illustrating one position of adjustment thereof.

DESCRIPTION OF THE INVENTION Referring now to the drawings, and more particularly to FIGS. 1 and 2 thereof, there is shown generally at 10 a roll feed mechanism embodying the instant invention. The mechanism 10 is supported by a housing comprising a top wall 12 secured to vertical frame members 14 which in turn are secured to a fixed surface 16 which is fixedly connected to or in the alternative may form a part of the stamping press (not shown) with which the feed mechanism 10 cooperates.

A vertically extending shaft 18 is journaled for rotation between top 12 and bottom surface 16, said shaft being driven off of the main drive shaft of the stamping press by means of belt 20 which drives shaft 22 which in turn drives shaft 18 through gear housing 24. Fixed to shaft 18 for rotation therewith is a bottom bevel gear 26 and a top bevel gear 28. The gear 28 is keyed to shaft 18 by means of key 30 which interengages in keyway 32 in shaft 18, as shown most clearly in FIG. 5. Spring 34 normally urges gear 28 in a downward direction. Lower gear 26, drivingly engages a bevel gear 36 while upper gear 28 drivingly engages bevel gear 38 and since gear 26 engages gear 36 at the lower portion of the periphery, while gear 28 engaged gear 38 at the upper portion of its periphery, the gears 36 and 38 are simultaneously driven at the same speed but in opposite directions. The gear 36 is fixedly connected to lower shaft 40 while gear 38 is connected to upper shaft 42 in a manner hereinafter to be described. Shaft 40 carries a lower roll 44 while shaft 42 carries upper roll 46 whereby when shaft 18 is driven, the rolls 44 and 46 are driven in opposite directions to impart linear feed to strip stock 48 passing therebetween, as shown most clearly in FIG. 3.

In order that the feed of strip 48 be intermittent, it is necessary that means be provided for imparting a predetermined length of linear feed to the strip for each complete revolution of the rolls, 44 and 46. To this end the rolls 44 and 46 are provided with undercut portions 50 and enlarged portions 52.-It will be understood that the rolls are effective to feed the strip 48 only when the enlarged portions 52 are in driving engagement with each other, or expressed differently, are located at the nip of the rolls. At all other times the rolls are sufficiently spaced so as not to feed thestrip, it being understood that frictional drag means 54 engage the strip prior to the strip reaching rolls 44, 46 to maintain a constant drag on the strip which not only maintains proper tension in the strip while it is being fed, but at the same time holds the strips sufficiently so that it will not be fed unless the enlarged portions of rollers 44 and 46 are in driving engagement. The friction drag means 54 is generally conventional in nature and comprises a lower block 56 over which the strip passes and an upper block 58 which is floatingly mounted with respect to block 56 and which is resiliently urged thereagainst by means of springs 60 the compression of which may be adjusted by turning the threaded stud 62 on which the springs are mounted, all in a manner well known in the art. The friction drag means 54 is mounted to the assembly 10 by any suitable means, such as bracket 64, note FIG. 2. It will be understood, of course, that the friction drag means 54 is properly aligned with the nip of rolls 44 and 46 so that stock 48 passing through the friction drag means will be properly aligned for entry between rolls 44, 46, as shown most clearly in FIG. 3.

Since strip 48 will be fed only when the enlarged portions of rolls 44 and 46 are in engagement with each other it follows that the length of feed of strip 48 for each complete revolution of the rolls will be dependent upon the relative position of the rolls with respect to each other. More specifically, if the enlarged portion of the rolls coincide, as shown in FIG. 3, then the maximum length of feed of strip 48 will be obtained since the enlarged portions will be in engagement with each other for their full extent. By offsetting the enlarged portion with respect to each other, however, the feed of strip 48 may be decreased until no feed whatsoever exists, i.e., where the enlarged portions are completely offset with respect to each other and never make driving engagement. In order to ensure that the feed of the strip may be reduced to zero, it has been found necessary to provide the undercut over approximately 190 of the circumference of each roll. Although this slightly reduces the maximum length of feed obtainable, it has been found necessary to do this to permit reduction of the feed length to zero, since if the undercut portions and enlarged portions each extended for 180 of the circumference, it has been found that some minimal feed of the strip takes place, even when the enlarged portions are completely offset with respect to each other, since it has been found that the enlarged portions must be spaced at apart before the strip is completely released.

In order that the rolls 44 and 46 may effectively feed strip 48 when the enlarged portions 52 are in driving engagement, it is necessary that the said rolls be resiliently urged into engagement with each other. To this end, upper roll 46 and the shaft 42 on which it is mounted, is floatingly journaled by any suitable means, not shown, whereby the roll 46 is free for movement toward and away from roll 44. As will be seen most clearly in FIG. 5, shaft 42 has fixedly secured thereon an elongated tubular member 66 which in turn has fixedly secured thereon upper roll 46. Thus, shaft 42, tube 66 and roll 46 all rotate as a unit. A pair of spaced circular collars 68 rotatably receive tube 66 by means of needle bearings 70, said collars having a recessed upper portion that received therein the lower ends of springs 72. The springs 72 in turn engage the lower ends of stud 74 which are threadably attached to top surface 12. Thus it will be seen that the springs 72 function to urge the assembly comprising shaft 42, tube 66 and upper roll 46 downwardly into engagement with lower roll 44 and the compression of springs 72 may be easily adjusted simply by tightening or loosening the threaded studs 74.

Since it is essential to successful operation of the assembly 10 that strip 48 be driven only when the enlarged portions 52 are in driving engagement, it follows that means must be provided for maintaining the rolls 44 and 46 in spaced relation when either or both of the undercut portions 50 are located at the nip of the rolls. These spacing means comprise circular collars 76 (FIGS. 1 and 4) located at opposite sides of the rolls 44 and 46. The diameter of the collar 76 is approximately equal or slightly less than the diameter of enlarged portions 52 whereupon when the enlarged portions-52 are in driving engagement, the collar 76 will not prevent the rolls from feeding strip 48. On the other hand, the diameter of collar 76 is sufficiently greater than the diameter of undercut portions 50 so that when one or both of the undercut portions 50 are located at the nip of the rolls, the collars 76 on upper roll 46 engage the collars 76 on lower roll 44 so as to maintain the rolls sufficiently spaced so that they do not drivingly engage strip 48.

Springs 72 will automatically compensate for slight variations in thickness of strip 48, it being understood that where a slightly thicker strip 48 is being fed, shaft 42 and gear 38 connected thereto are free to move upwardly against the action of springs 72, due to the aforedescribed floating mounting of shaft 42. As shaft 42 and gear 38 move upwardly, gear 28, which drivingly engages gear 38, will also slide upwardly on shaft 18 against the action of spring 34, it being understood that spring 34 will always urge gear 28 into engagement with gear 38 no matter what the thickness of stock 48.

As previously stated, the amount of strip 48 that will be fed for each revolution of rolls 44 and 46 is determined by the rotational adjustment of said rolls with respect to each other. To this end, first and second adjustment means are provided. The first adjustment means permits the upper roll 46 to be rotationally adjusted with respect to gear 38 in order to obtain the basic adjustment between rolls 44 and 46 which, as previously described, will determine the length of incremental feed of strip 48. The second adjustment means comprises an in-motion adjustment which permits a fine rotational adjustment of roll 44 to be achieved while the assembly 10 is operating. This fine adjustment permits a rotational adjustment of roll 44 of approximately up to plus or minus one-quarter of an inch. These adjustment means will now be described in detail.

Referring to FIG. 5 it will be seen that shaft 42 is provided with a tapered end 78 which is wedgingly received by a tapered bore 80 in gear 38. As will be seen in FIG. 5, shaft 42 is hollow and has a threaded pin 82 extendingly longitudinally therethrough, with one end of the pin 82 threadedly received by gear 28. The other end of pin 82 carries a washer 84 and has a nut 86 threadedly attached whereupon as nut 86 is tightened on pin 82, shaft 42 is wedged into locking engagement with gear 38. Thus, when it is desired to rotationally adjust roll 46 with respect to roll 44 it is simply necessary to loosen the nut 86 and then turn shaft 42 until roll 46 assumes the desired rotational adjustment with roll 44. In order to facilitate turning of shaft 42 a hand wheel 88 is secured thereto and is located adjacent nut 86. Openings 90 are provided in hand wheel 88 to receive any suitable pin or wrench to facilitate turning of wheel 88 and shaft 42.

The means for effecting fine adjustment of roll 44 will now be described. Referring to FIG. 7, it will be seen that the shaft 40 which is fixedly connected to gear 36 has mounted thereon a tubular member 92 which member is rotatable with respect to shaft 40. Roll 44 is fixedly secured to tubular member 92 so as to rotate therewith as a unit. As will be seen in FIG. 7, shaft 7 40 at its end remote from gear 38, extends outwardly beyond tubular member 92 and is provided with a pair of helical grooves 94. The adjacent end of tubular member 92 is provided with a pair of diametrically opposed longitudinal slots 96. As will be seen in FIG. 6, shaft 40 and tubular member 92 extend through frame 14 and tubular member 92 is journaled for rotation therein as at 98. An actuating element, shown generally at in FIG. 7, comprises an enlarged tubular portion l02ihaving inwardly extending longitudinal ribs 104 that slidably engage the aforesaid slots 96 whereupon element 100 is free to move longitudinally with respect to tubular member 92 but is fixed therewith for rotation. The element 100 further comprises a reduced tubular portion 106 that surrounds the exposed end of shaft 40, said portion 106 having a pair of inwardly extending helical ribs 108 that interengage with the aforesaid helical grooves 94. It will therefore be seen that if element 100 is moved longitudinally, the helical ribs 108 and grooves 94 will cooperate to cause relative rotation to take place between element 100 and shaft 40. Since, however, shaft 40 is fixed against rotation when gear 36 is stationary, it follows that the element 100 will rotate slightly, at the same time imparting corresponding rotation to tubular member 92 due to the interengagement of ribs 104 and slots 96. Thus, in and out movement of element 100 with respect to shaft 40 and tubular member 92 will result in turning movement of tubular member 92 and roll 44 which is fixedly mounted thereon.

The means for imparting in and out movement to element 100 will now be described. Referring to FIGS. 10 and 6, it will be seen that the element 100 is rotatably carried by an upright bracket 110 having a base portion 112 which is keyed to support 16 for slidable movement with respect thereto. More specifically, a track 114 slidably engages a corresponding groove or keyway 116 in the lower surface of base 112 and means are provided for imparting sliding movement to the upright bracket 110 so as to impart corresponding movement to element 100 since the element 100 is secured to portion 110 since the latter is located between lock washer 118 mounted in groove 119 on shaft 40, and the shoulder 120 which separates enlarged portion 102 from reduced portion 106. As previously mentioned, element 100 is journaled for rotationin bracket 110 by means of bearings 122. An upwardly extending arm 124 is secured to the end of support 16 and said arm threadedly receives adjusting screw 126, the threaded end of which is connected to bracket 110 by any suitable means, as illustrated, for example, at 128. Thus as adjusting screw 126 is turned, longitudinal sliding movement is imparted to bracket 110, the base 1 12 of which slidably moves along trackway 114 provided on the upper surface of support 16. Screw 115 cooperates with slot 117 to maintain base 112 in engagement with trackway 114 and at the same time to define the limits of slidable movement of base 112. As bracket 110 moves, it carries therewith actuating element 100 which in turn imparts a small degree of rotation to tubular member 92 and roll 44 mounted thereon in the manner hereinbefore described. As will be obvious, this adjustment can be easily accomplished while the assembly is in full operation thus permitting a fine adjustment of the length of feed of strip 48 to be accomplished without the necessity of having to shut down the stamping press with which assembly 10 is associated.

What is claimed is:

1. An adjustable roll feed assembly comprising a pair of rolls mounted in adjacent relation for receiving a strip of material therebetween, means normally urging said rolls toward each other, means imparting opposite rotation to said rolls in order to effect linear feed of the strip, and adjustment means associated with said rolls permitting the length of linear feed of the strip per revolution of said rolls to be adjusted, said adjustment means comprising undercut and enlarged portions on each of said rolls, means maintaining said rolls in spaced relation whereby said rolls drive said strip only when said enlarged portions are in engagement with each other, first means permitting at least one of said rolls to be rotationally adjusted with respect to the other, and second means for making a fine rotational adjustment of one of said rolls with respect to the other while the rolls are rotating.

2. The assembly of claim 1 further characterized in that said first means is applied to a first roll and said second means to a second roll.

3. The assembly of claim 2, further characterized in that said means for imparting opposite rotation to said rolls comprise a drive shaft having spaced gears thereon, said rolls each being mounted on shafts having gears in engagement with said drive shaft gears, said second means comprising a tubular member mounted on said second roll shaft, said member being rotatable with respect to said shaft and having the roll fixedly mounted thereon, one end of said shaft extending outwardly beyond the adjacent end of said tubular member, an actuating element surrounding said one end of said shaft and said adjacent end of said tubular member, means for imparting axial movement to said actuating element, cooperating helical means on said actuating element and said one shaft end whereby as axial movement is imparted to said element, it is caused to rotate relative to said shaft, and key means interconnecting said actuating element and said tubular member whereby they rotate as a unit but at the same time are free to move axially with respect to each other.

4. The assembly of claim 1, further characterized in that said means for imparting opposite rotation to said rolls comprise a drive shaft having spaced gears thereon, said rolls each being mounted on shafts having gears in engagement with said drive shaft gears, said first means comprising a tapered end on one of said roll shafts, a cooperating tapered bore on the gear carried bysaid shaft, and releaseable means wedging said tapered end into said tapered bore to connect said shaft and gear so that they rotate as a unit, said releaseable means being operable to release said wedge lock whereby said roll shaft may be rotated with respect to its gear to effect the desired rotational adjustment of said roll shaft, said second means comprising a tubular member mounted on said other roll shaft, said member being rotatable with respect to said shaft and having the roll fixedly mounted thereon, one end of said shaft extending outwardly beyond the adjacent end of said tubular member, an actuating element surrounding said one end of said shaft and said adjacent end of said tubular member,

means for impartin axial movement to said actuating element, cooperating ehcal means on said actuating element and said one shaft end whereby as axial movement is imparted to said element, it is caused to rotate relative to said shaft, and key means interconnecting said actuating element and said tubular member whereby they rotate as a unit but at the same time are free to move axially with respect to each other.

5. An adjustable roll feed assembly comprising a pair of rolls mounted in adjacent relation for receiving a strip of material therebetween, means normally urging said rolls toward each other, means imparting opposite rotation to said rolls in order to effect linear feed of the strip, and adjustment means associated with said rolls permitting the length of linear feed of the strip per revolution of said rolls to be adjusted, said adjustment means comprising undercut and enlarged portions on each of said rolls, said undercut portions extending for approximately of the circumference of each roll, means maintaining said rolls in spaced relation whereby said rolls drive said strip only when said enlarged portions are engagement with each other, and first means permitting at least one of said rolls to be rotationally adjusted with respect to the other.

6. An adjustable roll feed assembly comprising a pair of rolls mounted in adjacent relation for receiving a strip of material therebetween, means normally urging said rolls toward each other, means imparting opposite rotation to said rolls in order to effect linear feed of the strip, and adjustment means associated with said rolls permitting the length of linear feed of the strip per revolution of said rolls to be adjusted, said adjustment means comprising undercut and enlarged portions on each of said rolls, means maintaining said rolls in spaced relation whereby said rolls drive said strip only when said enlarged portions are in engagement with each other, and first means permitting at least one of said rolls to be rotationally adjusted with respect to the other, said means for imparting opposite rotation to said rolls comprising a drive shaft having spaced gears thereon, said rolls each being mounted on shafts having gears in engagement with said drive shaft gears, said first means comprising a tapered end on one of said roll shafts, a cooperating tapered bore on the gear carried by said shaft, and releaseable means wedging said tapered end into said tapered bore to connect said shaft and gear so that they rotate as a unit, said releaseable means being operable to release said wedge lock whereby said roll shaft may be rotated with respect to its gear to effect the desired rotational adjustment of said roll shaft. 

1. An adjustable roll feed assembly comprising a pair of rolls mounted in adjacent relation for receiving a strip of material therebetween, means normally urging said rolls toward each other, means imparting opposite rotation to said rolls in order to effect linear feed of the strip, and adjustment means associated with said rolls permitting the length of linear feed of the strip per revolution of said rolls to be adjusted, said adjustment means comprising undercut and enlarged portions on each of said rolls, means maintaining said rolls in spaced relation whereby said rolls drive said strip only when said enlarged portions are in engagement with each other, first means permitting at least one of said rolls to be rotationally adjusted with respect to the other, and second means for making a fine rotational adjustment of one of said rolls with respect to the other while the rolls are rotating.
 2. The assembly of claim 1 further characterized in that sAid first means is applied to a first roll and said second means to a second roll.
 3. The assembly of claim 2, further characterized in that said means for imparting opposite rotation to said rolls comprise a drive shaft having spaced gears thereon, said rolls each being mounted on shafts having gears in engagement with said drive shaft gears, said second means comprising a tubular member mounted on said second roll shaft, said member being rotatable with respect to said shaft and having the roll fixedly mounted thereon, one end of said shaft extending outwardly beyond the adjacent end of said tubular member, an actuating element surrounding said one end of said shaft and said adjacent end of said tubular member, means for imparting axial movement to said actuating element, cooperating helical means on said actuating element and said one shaft end whereby as axial movement is imparted to said element, it is caused to rotate relative to said shaft, and key means interconnecting said actuating element and said tubular member whereby they rotate as a unit but at the same time are free to move axially with respect to each other.
 4. The assembly of claim 1, further characterized in that said means for imparting opposite rotation to said rolls comprise a drive shaft having spaced gears thereon, said rolls each being mounted on shafts having gears in engagement with said drive shaft gears, said first means comprising a tapered end on one of said roll shafts, a cooperating tapered bore on the gear carried by said shaft, and releaseable means wedging said tapered end into said tapered bore to connect said shaft and gear so that they rotate as a unit, said releaseable means being operable to release said wedge lock whereby said roll shaft may be rotated with respect to its gear to effect the desired rotational adjustment of said roll shaft, said second means comprising a tubular member mounted on said other roll shaft, said member being rotatable with respect to said shaft and having the roll fixedly mounted thereon, one end of said shaft extending outwardly beyond the adjacent end of said tubular member, an actuating element surrounding said one end of said shaft and said adjacent end of said tubular member, means for imparting axial movement to said actuating element, cooperating helical means on said actuating element and said one shaft end whereby as axial movement is imparted to said element, it is caused to rotate relative to said shaft, and key means interconnecting said actuating element and said tubular member whereby they rotate as a unit but at the same time are free to move axially with respect to each other.
 5. An adjustable roll feed assembly comprising a pair of rolls mounted in adjacent relation for receiving a strip of material therebetween, means normally urging said rolls toward each other, means imparting opposite rotation to said rolls in order to effect linear feed of the strip, and adjustment means associated with said rolls permitting the length of linear feed of the strip per revolution of said rolls to be adjusted, said adjustment means comprising undercut and enlarged portions on each of said rolls, said undercut portions extending for approximately 190* of the circumference of each roll, means maintaining said rolls in spaced relation whereby said rolls drive said strip only when said enlarged portions are engagement with each other, and first means permitting at least one of said rolls to be rotationally adjusted with respect to the other.
 6. An adjustable roll feed assembly comprising a pair of rolls mounted in adjacent relation for receiving a strip of material therebetween, means normally urging said rolls toward each other, means imparting opposite rotation to said rolls in order to effect linear feed of the strip, and adjustment means associated with said rolls permitting the length of linear feed of the strip per revolution of said rolls to be adjusted, said adjustment means comprising undercut and enlarged portions on each of Said rolls, means maintaining said rolls in spaced relation whereby said rolls drive said strip only when said enlarged portions are in engagement with each other, and first means permitting at least one of said rolls to be rotationally adjusted with respect to the other, said means for imparting opposite rotation to said rolls comprising a drive shaft having spaced gears thereon, said rolls each being mounted on shafts having gears in engagement with said drive shaft gears, said first means comprising a tapered end on one of said roll shafts, a cooperating tapered bore on the gear carried by said shaft, and releaseable means wedging said tapered end into said tapered bore to connect said shaft and gear so that they rotate as a unit, said releaseable means being operable to release said wedge lock whereby said roll shaft may be rotated with respect to its gear to effect the desired rotational adjustment of said roll shaft. 